coding_freshmen/JAVA/QWERTY/ROMAN_TO_DECIMAL.java
import java.util.*;
 
public class RomanToNumber {
    // This function returns
    // value of a Roman symbol
    int value(char r)
    {
        if (r == 'I')
            return 1;
        if (r == 'V')
            return 5;
        if (r == 'X')
            return 10;
        if (r == 'L')
            return 50;
        if (r == 'C')
            return 100;
        if (r == 'D')
            return 500;
        if (r == 'M')
            return 1000;
        return -1;
    }
 
    // Finds decimal value of a
    // given roman numeral
    int romanToDecimal(String str)
    {
        // Initialize result
        int res = 0;
 
        for (int i = 0; i < str.length(); i++) {
            // Getting value of symbol s[i]
            int s1 = value(str.charAt(i));
 
            // Getting value of symbol s[i+1]
            if (i + 1 < str.length()) {
                int s2 = value(str.charAt(i + 1));
 
                // Comparing both values
                if (s1 >= s2) {
                    // Value of current symbol
                    // is greater or equalto
                    // the next symbol
                    res = res + s1;
                }
                else {
                    // Value of current symbol is
                    // less than the next symbol
                    res = res + s2 - s1;
                    i++;
                }
            }
            else {
                res = res + s1;
            }
        }
 
        return res;
    }
 